Why you were just 'unfriended' on Facebook

In the internet age, it is the ultimate snub. So why do people unfriend each other?

Obviously, what people post can strain their online relationships, but not having a mutual female friend is much more likely to lead to the ties being severed.

The word "unfriending" entered common vocabulary only a few years ago, and since then researchers have been trying to understand why and when it happens. The answers relate to a bigger outstanding question in web science: are online social relationships fundamentally different to physical world ties? The likes of Facebook also want to know what drives unfriending, because decaying friendships is bad for business.

Up until now, the evidence suggested that unfriending on online social networks was driven mainly by too-frequent posts about polarising topics. Too much religion? Goodbye. Support gay marriage? Unfriend. And in a recent survey of US adults, 55 per cent said they unfriended people because of their offensive status updates or comments. That was the most popular reason, followed by "not knowing the person well" (41 per cent), and "tried to sell me something" (39 per cent).

So far, so unsurprising.

Yet Daniele Quercia at
the University of Cambridge had doubts about whether politics and
rudeness really were the most common reasons for severing Facebook ties.
After all, he says, these recent studies and surveys were based on
self-reported behaviour, not hard data. And more importantly,
the reasons people gave for severing their Facebook ties are not the
same factors that lead to the dissolution of offline
relationships.

For example, studies dating back to the 1980s show that friendships have
always been more likely to decay when there are fewer common ties with
others in a social group ("embeddedness") and a disparity between age,
occupation and education. So while your buddy might make the occasional
sexist joke you dislike, that is much less likely to influence the fate
of your friendship than whether or not you have mutual friends, are the
same age and both work in IT.

Sure enough, a lack of similarity, especially between ages, and few
mutual friendships were the dominant factors correlating with
unfriending - all of which mirrors the decline of physical-world
relationships. Quercia also found that having a mutual female friend makes unfriending less
likely than sharing a male friend. Clues as to why
come from research conducted by Robert Bell in the 1980s on gender roles
in friendship. In short, Bell showed that women tend to form deeper,
stronger friendships, and they strengthen relationships beyond their direct ties in their social network.

Finally, Quercia also showed that personality type matters. Perhaps not
surprisingly, a relationship is more likely to break if one of the
people is neurotic or introverted.

Facebook may be a new environment, but the age-old rules of friendship apply there too.